Question

The velocity of electron in the ground state hydrogen atom is 2.18$\times 10^{8}ms^{- 1}.$ Its velocity in the second orbit would be

• A. $1.09 \times 10^{8}ms^{- 1}$
• B. $4.38 \times 10^{8}ms^{- 1}$
• C. $5.5 \times 10^{5}ms^{- 1}$
• D. $8.76 \times 10^{8}ms^{- 1}$

Answer 1

Answer: (A)

$1.09 \times 10^{8}ms^{- 1}$

Answer 2

We know that velocity of electron in n^th Bohr's orbit is given by

$v = 2.18 \times 10^{6}\frac{Z}{n}m/s$

for $H,Z = 1$

$\because$ $v_{1} = \frac{2.18 \times 10^{6}}{1}m/s$

$\because$ $v_{2} = \frac{2.18 \times 10^{6}}{2}m/s = 1.09 \times 10^{6}m/s$